Echinocandin Resistance in Candida albicans
Introduction ''Candida albicans'' is a diploid fungus that can grow as both yeast and filamentous cells. It normally resides in the intestinal tract, mouth, and vagina in humans, however, when the body's normal microbiota is disturbed, it can overgrow and cause opportunistic infections (1). ''C. albicans'' infections are minor in those with healthy immune systems, however, this fungal infection causes a great amount of morbidity and mortality in those who are immunocompromised. ''C. albicans ''can form biofilms on metal devices and is a dangerous nosocomial infection (1). In patients with healthy immune systems, ''Candida albicans ''infections can be treated by the use of antifungals. For vaginal yeast infections, a single treatment of fluconazole through vaginal suppositories or medicated douches is 90% effective in clearing the infection. In breast feeding babies, gentian violet, an antiseptic dye, may be used in small amounts. For skin infections, application of clotrimazole creams multiple times a day can clear the infection quickly. If the ''C. albicans'' infection is in the blood, an intravenous fluconazole or an echinocandid may be used (1). Genetic Study The more drugs used to clear fungal infections, the greater the risk for development of antifungal resistance. One way ''Candida albicans'' can become resistant is through the build up of chitin in the cell wall. In 2012, a study was done to investigate the effect elevated chitin levels in ''Candida albicans'' cell walls had on echinocandin susceptibility ''in vivo''. In this study, a group of BALB/c mice were infected with ''C. albicans'' cells with normal chitin levels and another group of BALB/c mice were infected with ''C. albicans'' with a high-chitin level. 24 hours after infection, all the mice were treated with caspofungin, a type of echinocandin. Then 24 hours after the first treatment, the mice received a second dose of caspofungin (4). Results When caspofungin was administered 24 hours after infection, the mice infected with a normal chitin level ''Candida albicans'' were successfully treated. There was a reduction in kidney fungal burdens, a decreased ''C. albicans'' density in kidney lesions, and the mice stopped losing weight. However, the mice that were infected with ''C. albicans'' with high chitin levels had a minimal response to caspofungin; they had a greater number of fungal burdens and a greater unintended weight loss. ''C. albicans ''cells were then recovered from the mice with higher-chitin levels and tested. The cells had a 1.6-fold higher chitin level than the cells with normal chitin. 48 hours after the initial infection, the caspofungin treatment showed to have further increase the chitin in ''C. albican'' cells. The recovered clones' genomes were tested, which showed there was an acquired point mutation in the FKS1 gene. This point mutation resulted in an amino acid substitution, enhancing echinocandid resistance. The results of this test suggests that ''Candida albicans ''can in fact become less suseptible or resistant against echinocandins if there is a high level of chitin in the cell wall or if there is a point mutation in the FKS1 gene (1). Resources 1) [http://www.medicinenet.com/script/main/art.asp?articlekey=11072 Definition of Candida albicans]. MedicineNet. 2) [[wikipedia:Candida_albicans|Candida albicans.]] Wikipedia. 3) [[wikipedia:Candidiasis#Treatment|Candidiasis.]] Wikipedia. 4) [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256049/ Elevated Cell Wall Chitin in ''Candida albicans'' Confers Echinocandid Resistance In Vivo]. PubMed.